FREQUENTLY ASKED QUESTIONS
This page contains answers to some common questions about how AlcoTrace Professional works and can be used.
Does AlcoTrace Professional use a fixed Widmark value?
No. In Widmark algorithms employed by other programs, a fixed Widmark R of 0.68 is typically used. This can result in errors if the subject's lean body weight differs significantly from actual weight, and the user is asked to enter a more suitable Widmark R value. This requires that the user have extensive knowledge and expertise in toxicological analysis. AlcoTrace Professional computes a Widmark R based on individual height and weight which is more reliable than using a constant Widmark R of 0.68. The program employs a complex yet fast algorithm which computes the Widmark r for every case, freeing the user from deciding on an arbitrary Widmark factor. Though less accurate, a model based on weight alone is retained in AlcoTrace Professional for use as an option.
Our technical paper:
D.W. Rockerbie, R.A. Rockerbie, "Computer Simulation Analysis of Blood Alcohol", Journal of Clinical Forensic Medicine, Vol. 2, 1995, 137-41.
Is alcohol consumption assumed to be instantaneous?
Absolutely not. AlcoTrace Professional requires the user to enter a start and an end time of drinking for each drink consumed. Consumption is assumed to be evenly spaced over this period. In cases of heavy drinking, assuming instantaneous consumption can seriously overestimate blood alcohol concentration buildup.
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- Generate informative reports
- Display results in graph format
- Export results to MSWord and MSExcel
- Use default or user specified elimination rates
- Choose Widmark or Michaelis-Menton methods
- Zero order and first order elimination
- Flexible alcohol absorption rates
- Enter multiple beverages over different time periods
- No limit to number of entries
- Perform "what if" simulations
ALCOTRACE
PROFESSIONAL
Must the user specify the absorption period?
The rate of alcohol absorption is markedly dependent on a number of factors including body size, gender, presence of food, and the type of beverage. The absorption rate is not constant but actually slows down as the volume of alcohol remaining to be absorbed is reduced. AlcoTrace Professional considers each of these factors, and computes the amount absorbed at any point in time for the purpose of the Widmark formula. The guesswork and error associated with methods which assume complete absorption, or ask the user to specify an absorption period, is eliminated.
Why does AlcoTrace Professional use a maximum and minimum elimination rate instead of just an average of the two?
On the average, the alcohol concentration declines at approximately 17 mg (0.017g) of alcohol per 100 ml per hour from the blood. However wide deviations exist in the general population from this average. Fortunately 95% of individuals fall somewhere in the 10 - 24 mg (0.01 -0.024 g) per hour range, which is the default setting used by AlcoTrace Professional. If a simple elimination rate is used, and the assumed elimination rate is incorrect, the entire analysis is cast into doubt. This situation can be avoided by using a range of elimination rates. Of course the default elimination rates used by AlcoTrace Professional can be easily changed to any level desired. At low concentrations, the elimination rate in the body is concentration dependent. AlcoTrace Professional simulates the human body by using Widmark's reduced elimination formula at the level of drinking and in the later elimination phase.
Just how accurate is the algorithm utilized by AlcoTrace Professional?
AlcoTrace Professional has undergone extensive field testing utilizing a large number of actual cases. Comparisons of AlcoTrace Professional simulations with controlled drinking studies reported by others (A.W. Jones (1993)) show AlcoTrace Professional to be very accurate and a reliable tool for blood alcohol simulations. See our technical paper for further results.